Filters are used to clean and remove debris from a wide variety of automotive fluids. For example, oil filters filter engine oil, transmission filters filter automatic transmission fluid, and coolant filters filter engine coolant as it circulates through the engine. Filters also may be used to filter air conditioning refrigerant as it circulates into and/or out of the compressor of an automotive air conditioning system. In this regard, my previous U.S. Pat. No. 6,176,093 issued on Jan. 23, 2001 discloses an automotive air conditioning refrigerant filter and method wherein a thimble-shaped filter element is installed in an air conditioning compressor to trap debris that may be entrained in the refrigerant. The disclosure of this patent is hereby incorporated by reference.
A unique aluminum tubing coupler is used in many automotive air conditioning systems to couple together the ends of two pieces of aluminum tubing. Such a coupler is used, for instance, to couple the condenser unit of the air conditioning system in the refrigerant line from the compressor. A coupler is the ideal location in many instances where a refrigerant filter can be inserted in the refrigerant line because there is a natural break in the line at this location. However, the tubing couplers mentioned above often are located in tight or cramped quarters within an engine compartment such as, for instance, between the condenser unit and the firewall or within the radiator cowling. For this reason, it often is impossible to install a traditional in-line type filter unit in the refrigerant line because there simply is not enough space to accommodate such a filter unit. Smaller in-line filters may be selected to fit the space, but the correspondingly smaller area of filter media in these smaller filters generally is unacceptable because the filter clogs quickly and must be replaced often. Replacement is a problem in the cramped and sometimes inaccessible quarters in which the filters reside.
Thus, there is a need for an automotive air conditioning filter unit that can easily be installed in cramped and tight locations where tubing couplers of the system are located but that nevertheless provides a large filter media area that effectively filters for a long period of time without becoming clogged. It is to the provision of such a filter unit that the present invention is primarily directed.